先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/27 14:40:13
![先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7](/uploads/image/z/1072775-47-5.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%E5%9C%A8%E6%B1%82%E5%80%BC+%EF%BC%88x%2B5y%EF%BC%89%EF%BC%88x%2B4y%EF%BC%89-%EF%BC%88x-y%EF%BC%89%EF%BC%88x%2By%EF%BC%89%2C%E5%85%B6%E4%B8%AD%2Cx%3D-2%E5%8F%882%2F3%2Cy%3D3%2F7)
先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7
先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7
先化简在求值 (x+5y)(x+4y)-(x-y)(x+y),其中,x=-2又2/3,y=3/7
(x+5y)(x+4y)-(x-y)(x+y)
=x²+9xy+20y²-x²+y²
=9xy+21y²
=9×(-2又2/3×3/7)+21×(3/7)²
=-72/7+27/7
=-45/7
我类个去,这么男哦啊。。出